I purchased a '97 GTP Sedan a months ago with about 194K miles. I kept getting an intermittent "low coolant light" last week (though it wasn't running hot). I popped the overflow bottle open to find it full of brown "gunk". I drained to coolant system and could see from looking down the top of the radiator with a light that the radiator is badly rusted. I flushed the coolant system completely twice in both directions and used Preston Coolant cleaner. I did eventually get the flush water to run clean in both directions for over 10 minutes, but upon inspection the radiator still looks to be in a pretty bad way. I priced a few replacement radiators, and while not expensive, I am concerned that the rust may have affected the water pump, hoses, and heater core as well. Since the flush, the engine is running even cooler that before and my heat works better than ever, so I am not sure if I need to panic and drop a lot of time and money just yet. Suggestions?
Also, I noticed after the flush that I no longer have AC. When performing the flush, I ran the heater on high as per the instructions, and now it only blows heat. If I turn the control on the dash to cold, the air blowing in through the vents never changes. I don't think it is low on freon or anything, because it isn't "luke-warm" outside air, but hot heat as if I still had it set to the max heat setting. I am assuming the switch just not longer works. What parts do I need to replaces, and how do I go about doing so?
